Síntese e avaliação da atividade antioxidante de novos derivados imidazo[4,5-c]4,5,6,7-tetraidropiridina contendo os grupos 4-fluorfenil e 3- hidroxifenil na posição-4

Abstract

Currently have been shown a significant increase in the use and evaluation of antioxidant capacity, both in pharmaceuticals and cosmetics and in food and natural products, in particular compounds containing the imidazole group in their structures. These derivatives have a wide range of biological activities such as antibacterial, antituberculosis, antifungal, anticonvulsant, anti-inflammatory, antitumor, analgesic and antioxidant. This paper presents the synthesis and evaluation of the antioxidant activity of new derivatives containing the imidazole ring. The compounds were synthesized by the condensation reaction of the Pictet-Spengler L-histidine to 4-flúorbenzaldeído and 3-hydroxybenzaldehyde, followed by esterification reaction. The structures of synthesized compounds were confirmed based on analysis of the spectral data NMR 1 H. Two novel compounds were synthesized 6-carboxy-4-phenylssubstitutedimidazo[4,5-c] 4,5,6,7-tetrahydropyridine 36a and 36b in yields of 86.4% and 49.4%, and a new compound 6-carbomethoxy-4-phenylssubstituted-imidazo[4,5-c]4,5,6,7-tetrahydropyridine 37b, yield 93.3%. The derivatives were subjected to in vitro evaluation of antioxidant activity for the method of free radicals DPPH and ABTS. The results of IC50 and %S of ABTS radical, obtained for the synthesized derivatives have shown that the compound 37b showed the highest antioxidant activity by DPPH method and 36b showed better potential antioxidant by method ABTS, however showed potential smaller than the standard BHT.